We estimate the general deterrent effect of criminal justice resources
on criminal behavior using panel data for a sample representative of
young men in U.S. urban areas. Our data, which combine individual-leve
l information on arrests and personal characteristics with aggregate i
nformation on criminal justice resources, allow us to obtain deterrenc
e measures that reflect theoretical concepts and are of potential poli
cy relevance. We find robust evidence of a general deterrent effect fl
owing from criminal justice, particularly police, resources. The natur
e of our data also allows us to conduct extensive exogeneity tests and
to explore a number of possible ''third causes'' for the deterrent ef
fect. We find strong evidence that our deterrence variables are exogen
ous and no evidence that our deterrence result stems from commonly hyp
othesized third causes.